U.S. Pat. No. 4,825,970 (referred to herein as '970) issued to McVicar et al. on May 2, 1989, discloses a power take-off for a road vehicle. A significant disadvantage in the '970 patent is the inability to raise and lower the snowblower or adjust its elevation since it is fixed by insertion of bars into square tubes. Belt adjustment or removal on this is somewhat difficult and it is not clear how the belt adjustment works.
A second invention, U.S. Pat. No. 4,244,122, issued to Hitrick on Jan. 13, 1981, discloses a modified power unit for a snow plow attachment to a vehicle having an improved power piston to raise and lower the plow blade. Hydraulic power is obtained from an extra separately mounted, electric motor driven, gear-type oil pump.
The present invention overcomes the above shortcomings as described below:
a parallelogram, pivoting hitch frame is disclosed that can be easily raised and lowered using a hydraulic by-pass line from the power steering of a truck or pickup and maintains any tool or implement in a vertical orientation whether the implement is in a raised or lowered position or any continuum between the raised and lowered positions; PA1 the hitch is easily attached at only four points to the truck frame and two points to the bumper; PA1 the single-point attachment of the clutch/PTO drive assembly to the engine is easily adjustable for belt tension and the driven-hitch pulley remains at a fixed distance in spite of engine motion; PA1 the pivoting power take-off clutch is attached to the hitch and not the engine or vehicle frame; PA1 the power take-off spline is coupled to a double universal-joint drive shaft so that the output end rotates at a constant angular velocity; and PA1 the power take-off has a common universal tractor-type male spline used throughout the implement product lines. PA1 a frame bracket to attach to the vehicle frame; PA1 a pair of pivot arms pivotally attached to the frame bracket; PA1 hydraulic lift means mounted on the frame bracket for raising and lowering the pivot arms; PA1 a belt-driven power take-off mounted on the frame bracket connecting to a vehicle engine pulley through an electric clutch; PA1 electrical control means to control the hydraulic lift means and electric clutch; and PA1 wherein the implement is maintained in a vertical orientation in a raised and lowered position and in a continuum between the raised and lowered positions.